1. Field of the Invention
The present invention relates to a washing machine, more particularly to a washing machine equipped with an air bubble generator having contraction/enlargement exhaust nozzles for providing fine air bubbles of a very small diameter.
2. Description of the Prior Art
In general, washing machines are classified into two categories. The first one of the two categories includes a whirl-type washing machine in which washing articles are washed by a vortex flow of washing water formed in a washer tub when a pulsator is rotated. The second one includes a drum-type washing machine. The drum-type washing machine has a rotary drum a portion of which lies in the washing water. In such a rotary drum, the washing articles are put in the rotary drum. When the rotary drum is rotated, the washing articles in the rotary drum strike each other, so that the washing articles are washed.
In order to enhance washing efficiency of the drum-type washing machine, an air bubble generator for the drum-type washing machine is proposed. FIG. 1 is a schematic view of a conventional drum-type washing machine with an air bubble generator, FIG. 2 is an enlarged perspective view of the rotary drum of FIG. 1, and FIG. 3 is an enlarged perspective view of the air bubble generator of FIG. 1.
Hereinafter, the conventional drum-type washing machine with an air bubble generator will be described with reference to accompanying drawings.
In the vortex-flow type washing machine as shown in FIG. 1, the washer tub 20 is mounted to be rotated in the reservoir 10. An air bubble generator 30 is mounted on the bottom of the reservoir 10. Air is supplied through an inlet 35 by an air pump(not shown). A pulsator 23 for generating the vortex flow is mounted to be rotated on the washer tub 20. An air bubble passageway 25 is formed in the bottom of the washer tub 20. An outlet 15 is formed in the bottom of the reservoir, that is, under the air bubble generator 30.
The drum type washing machine as shown in FIG. 2 has a housing 40 and a reservoir 50 mounted in the housing 40 for accommodating washing water. A rotary drum(hereinafter, called ?a drum?) 60 has a plurality of through-holes 64 for washing water to flow in and out of the drum 60. The drum 60 includes traverse slits 68 for washing water to flow in the drum 60, and the traverse slits 68 are formed in the surface of the drum 60 in parallel with the shaft(not shown) of the drum 60. A part of the drum 60 lies in the washing water. An air bubble generator 70 is mounted on the bottom of the reservoir 50. The air bubble generator 70 is supplied with compressed air through a conduit 75.
FIG. 3 shows an air bubble generator capable of being applied to the washing machines of FIGS. 1 and 2.
The air bubble generator includes an inlet 84 adapted to be connected with an air pump (not shown) and a case 80 in which water flow-out portions 88 are formed in a slantedly opposite manner and opposite to the inlet 84. A porous member 85 is mounted in the case 80 between the inlet 84 and the water flow-out portions 88. Air flowing in through the air pump moves into the washing water through the porous member 85. The air flowing out of the porous member 85 is converted into fine air bubbles. An air bubble-generating plate(hereinafter, called ?a plate?) 90 having a plurality of outlets 94 is closely contacted with the water flow-out portions 88. An elastic plate 98 is further provided, one end of which is fixed on an upper end of the plate 90 so that air bubbles from the plate 90 are prevented from moving further up. As the air bubble generator is operated, the other end of the elastic plate 98, which is movable, is opened by air bubbles flowing out of the outlets 94. Each of the outlets 94 is in a cylindrical shape with a uniform diameter from the bottom to the top thereof.
Operations of the conventional air bubble generator as mention above will be described hereinafter.
As the air bubble generator is operated, compressed air flowing in through the inlet 84 is converted into fine air bubbles by the porous member 85, as shown in FIGS. 1 and 2. The fine air bubbles are dispersed into washing water through the outlets 94. The dispersed air bubbles serve to wash washing articles such as clothing by moving into the reservoir 20 or 50.
However, in the air bubble generator, some air bubbles may block the outlets 94 or may break since air bubbles may have a larger diameter than the outlets have. Accordingly, less air bubbles may be produced from the plate, so that less air bubbles flow into the reservoir and washing efficiency is deteriorated. Further, air bubbles move nearer to the washing water surface by buoyancy of the washing water. At this time, the water pressure with respect to the air bubbles becomes less, so that the size of an air bubble becomes larger enough to distort the shape of the air bubble. Accordingly, the washing efficiency can be obtained by fully generating fine air bubbles.